1. Field of the Invention
This invention relates to a proximity detector, the orientation of the head being adjustable.
Detectors of this kind are often switches which are used in installations or machinery in which the position of a component or movable metal object is required to be known. They may be fixed on a support which has one out of, for example, five specific positions relative to the movement of said object. In one of these positions a detector surface of the head must be oriented frontally instead of laterally in the case of the other positions.
The invention relates more particularly to a proximity detector comprising a casing, a mount adapted to be positioned on the casing in a number of orientations selectively about an axis and a detector head adapted to be connected to the mount in two orientations selectively, in one of which the detection direction is parallel to said axis while in the other of the two orientations the detection direction is a radial direction relative to the axis, such radial direction being defined by the orientation of the mount about the axis, the mount and the detector head together forming substantially a cube, a first edge of which is defined by the mount, the head being fixed to the mount by two screws which in each of the two orientations of the head relative to the mount extend along two second edges of the cube which are not concurrent to one another but which are both concurrent with the first edge.
2. Description of the Related Art
According to DE-U-No. 72 15 121, which substantially describes this structure, the two second edges are parallel to one another and the screws occupy one or other of two pairs of holes in the head depending on whether the head is in one or other of its two orientations. The head must therefore have found holes along four "second edges" and this obstructs the space available inside. Also, the fixing obtained is not optimum as regards even kind of impact and stress which may occur.
It is also known, for example from DE-A-No. 2 914 713, to fix the detector head of a proximity detector to the body of the device by means of screws extending through two parallel oblique holes disposed in a diagonal plane of the head. The same pair of holes in the head can be used for the two orientations (frontal and lateral) of the head, but there is a considerable amount of space lost in the head. To limit this disadavantage, the screws provided according to this document are relatively short to the detriment of the strength of the fixing. By offsetting the holes relatively to the diagonal plane DE-U-No. 73 44 278 proposes a solution which allows space to be saved in the head but which on the other hand necessitates the provision of two pairs of holes in the mount, each receiving screws in one of the two orientations of the head relative to the mount. Despite that, the saving in space in the head is minimal because if the fixing is to be strong the oblique holes must not extend far from the diagonal plane.
The whole of this prior art clearly shows the difficulty in finding a compromise between strength and internal volume of this type of device. The need to find such a compromise is particularly acute at the present time. Firstly, the tendency is to increase the useful range of detectors by the use of large-diameter magnetizable pots and windings. Also, the attempt is made to improve the quality of detection by integrating electronic components connected to the windings in the detector head completely or partially.